1. Field of the Invention
The present invention relates to an image recording apparatus including a recording medium which stores an image signal and a voice signal, and, in particular, to an image recording apparatus which has coding/decoding function for the image signal or voice signal. The present invention also relates to a semiconductor device for embodying functions of this image recording apparatus.
2. Description of the Related Art
In recent years, image recording apparatuses which encode and compress input image signals (or video signals) and audio signals into MPEG 2 PS or TS data, store them, and, then, decode and decompress them have been put into the market of public welfare apparatuses. Such image recording apparatuses employ magnetic-disk recording media, or, recently, DVDs, as data recording media. In particular, an apparatus using a magnetic-disk recording medium is called a HDD recorder.
Generally, this type of image recording apparatus can perform recording/reproducing by a plurality of conditions, such as a high-quality mode, a standard mode, a low-quality (but long time recordable) mode, and so forth, by controlling data coding conditions, appropriately. Furthermore, as the seek time is shortened for such a recording medium as magnetic-disk recording medium, a so-called “time-shift function” is attained in which an arbitrary position of an image file can be reproduced while the same file is recorded onto the disk recording medium.
Such an image recording apparatus is generally connected both to a source external apparatus such a DVD player or the like from which image signal and audio signal to be recorded is input via an input terminal, and, to an output external apparatus such as a TV set or the like through which reproduced image signal and audio signal are output via an output terminal.
Then, there is a case where, the image recording apparatus inputs thereto the image signal and audio signal input from the source external apparatus, and, then, outputs these signals to the output external apparatus without storing the signals therein. In such a case, when the image recording apparatus has a provision (special path) for bypassing the input image and audio signals to the output terminal without coding, compressing, storing, decompressing and decoding the signals, the input signals are output as they are.
However, when the image recording apparatus does not have such a provision (special path), the input signals are output after being once coded, compressed, stored, decompressed and decoded. In such a case, when the coding/decoding bit rate has been set relatively lower (for example, on the above-mentioned low-quality mode) in the recording apparatus, the thus-output signals after being thus coded, stored and decoded are those somewhat degraded in quality. Thereby, the quality in image and audio thus output via the output external apparatus is not a satisfactory one.